A dye-sensitized solar cell contains, as its critical components, photosensitive dye molecules for absorbing visible light and a transition metal oxide layer for transferring electrons generated by the dye molecules. A representative example of a dye-sensitized solar cell has been reported by Gratzel et al. of Switzerland, and it comprises titanium dioxide (TiO2) nanoparticles, dye molecules adsorbed thereon, a semiconductor electrode, a platinum electrode, and an electrolytic solution interposed between the electrodes. This type of solar cell has the advantage of lower production cost than the conventional silicone solar cell.
In the preparation of a conventional dye-sensitized solar cell, a conductive substrate is directly coated with a colloidal solution of nanoparticular oxide and calcined at a temperature of 400 to 500° C. Although the calcination treatment is intended to remove the polymeric binder component of the colloidal solution and to improve the electrical contact between the nanoparticulated oxide layer and the substrate, even a slight physical impact thereon would often cause the detachment of the first conductive substrate and the nanoparticulated oxide layer.
Further, the conventional dye-sensitized solar cell has disadvantages in that the adhesion between the substrate and the nanoparticulated oxide layer is weak and that the transparency of the first conductive substrate is poor. Thus, the ability of transferring electrons generated by the dye molecules to the substrate is not efficient. Further, the passage of electrons through crystal boundaries of high electron density also hinders the electron transfer as well as light transmittance.